skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Reentrant nematic and multiple smectic-A liquid crystals: Intrachain flexibility constraints

Abstract

A recent new microscopic, molecular statistical-physics theory for the intrachain constraints on the n-alkyl tail-chain flexibility for molecules composed of rigid rodlike cores and n-alkyl tail chains in the smectic-A/sub 1/, smectic-A/sub d/, and nematic (including reentrant nematic) liquid-crystal phases and the isotropic liquid phase is used to calculate relative stabilities as well as various thermodynamic and molecular ordering properties (including odd-even effects) for these phases. The molecules can interact via these site-site intermolecular interactions: hard (steric) repulsions, various Lennard-Jones (LJ) potentials for soft repulsions and London dispersion attractions, and/or dipolar forces (dipole-dipole and dipole--induced-dipole). The theoretical results in this paper are in significantly better agreement with experiment than are results in earlier papers using older, more approximate theories. The effects of varying pressure, tail-chain flexibility, and intermolecular interactions on the relative stabilities of the multiple smectic-A phases and the reentrant nematic phase are presented. These relative phase stabilities are sensitive to subtle changes in these variables. Predictions and accompanying physical explanations are also made for various systems that have not yet been chemically synthesized and/or studied experimentally.

Authors:
Publication Date:
Research Org.:
Theoretical Division, Los Alamos National Laboratory, University of California, Los Alamos, New Mexico 87545
OSTI Identifier:
5922305
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Journal Article
Journal Name:
Phys. Rev. A; (United States)
Additional Journal Information:
Journal Volume: 36:10
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; LIQUID CRYSTALS; MOLECULAR STRUCTURE; PHASE STUDIES; ORGANIC COMPOUNDS; ALKYL RADICALS; CRYSTAL MODELS; CRYSTALLIZATION; ORDER PARAMETERS; CRYSTALS; FLUIDS; LIQUIDS; MATHEMATICAL MODELS; PHASE TRANSFORMATIONS; RADICALS; 360602* - Other Materials- Structure & Phase Studies

Citation Formats

Dowell, F. Reentrant nematic and multiple smectic-A liquid crystals: Intrachain flexibility constraints. United States: N. p., 1987. Web. doi:10.1103/PhysRevA.36.5046.
Dowell, F. Reentrant nematic and multiple smectic-A liquid crystals: Intrachain flexibility constraints. United States. https://doi.org/10.1103/PhysRevA.36.5046
Dowell, F. 1987. "Reentrant nematic and multiple smectic-A liquid crystals: Intrachain flexibility constraints". United States. https://doi.org/10.1103/PhysRevA.36.5046.
@article{osti_5922305,
title = {Reentrant nematic and multiple smectic-A liquid crystals: Intrachain flexibility constraints},
author = {Dowell, F},
abstractNote = {A recent new microscopic, molecular statistical-physics theory for the intrachain constraints on the n-alkyl tail-chain flexibility for molecules composed of rigid rodlike cores and n-alkyl tail chains in the smectic-A/sub 1/, smectic-A/sub d/, and nematic (including reentrant nematic) liquid-crystal phases and the isotropic liquid phase is used to calculate relative stabilities as well as various thermodynamic and molecular ordering properties (including odd-even effects) for these phases. The molecules can interact via these site-site intermolecular interactions: hard (steric) repulsions, various Lennard-Jones (LJ) potentials for soft repulsions and London dispersion attractions, and/or dipolar forces (dipole-dipole and dipole--induced-dipole). The theoretical results in this paper are in significantly better agreement with experiment than are results in earlier papers using older, more approximate theories. The effects of varying pressure, tail-chain flexibility, and intermolecular interactions on the relative stabilities of the multiple smectic-A phases and the reentrant nematic phase are presented. These relative phase stabilities are sensitive to subtle changes in these variables. Predictions and accompanying physical explanations are also made for various systems that have not yet been chemically synthesized and/or studied experimentally.},
doi = {10.1103/PhysRevA.36.5046},
url = {https://www.osti.gov/biblio/5922305}, journal = {Phys. Rev. A; (United States)},
number = ,
volume = 36:10,
place = {United States},
year = {1987},
month = {11}
}